Neurological stimulators have been developed to treat pain, movement disorders, functional disorders, spasticity, cancer, cardiac disorders, and various other medical conditions. Implantable neurological stimulation systems generally have an implantable pulse generator and one or more leads that deliver electrical pulses to neurological tissue or muscle tissue. For example, several neurological stimulation systems for spinal cord stimulation (SCS) have cylindrical leads that include a lead body with a circular cross-sectional shape and one or more conductive rings or bands spaced apart from each other at the distal end of the lead body. The conductive rings operate as individual electrodes and, in many cases, the SCS leads are implanted percutaneously through a large needle inserted into the epidural space either with or without the assistance of a stylet.
Once implanted, the pulse generator applies electrical signals via the electrodes to modify the function of the patient's nervous system, such as altering the patient's responsiveness to sensory stimuli and/or altering the patient's motor-circuit output. In pain treatment, the electrical signals can generate sensations which mask or otherwise alter the patient's sensation of pain. For example, in many cases patients report a tingling or paresthesia that is perceived as more pleasant and/or less uncomfortable than the underlying pain sensation. Although this may be the case for many patients, many other patients may report less beneficial effects and/or results. Accordingly, there remains a need for improving the techniques and systems for addressing patient pain.
One particular challenge of implementing neurological stimulators to manage pain is that multiple parts or regions of the patient's body contribute to the pain perceived by the patient, and the individual contributions of the various regions vary over time. For example, patients generally experience different levels of back pain and/or lower extremity pain because of exertion, stress, movement (e.g., walking, bending, twisting, etc.), position (e.g., standing, sitting, etc.), and other factors. Patients accordingly change the parameters of the electrical waveform in some or all of the affected regions on an ongoing basis to effectively manage the pain.